X-ray tube.



E. W. KELLY.

X-RAY TUBE.

APPLICATION FILED 1uu|:27. 1914.

@LM l@ .Y me?? Patented Nov. 16, 1915.

A'ITORN EY ff ESTA PA EDWIN W. KELLY, 0F PHILADELPHIA, PENNSYLVANIA,ASSIGNOR T0 SNOOK-YROENT- GEN MANUFACTURING COMPANY, OF PHILADELPHIA,PENNSYLVANIA, A- COB- PORATION OF PENNSYLVANIA.

X-RAY TUBE.

Patented Nov. 1e, 1915.

Application led .Tune 27, 1914. Serial o. 847,618.

To all whom it may concern.'

Be it known that I, EDWIN W. KELLY, acitizen of the United States,residing in the city of Philadelphia, county of Philadelphia, and Stateof Pennsylvania, have invented certain new and useful Improvements inX-Ray Tubes, of which the followingis a specification.

My invention relates to means for cooling a. vacuum tube, moreparticularly an X-ray tube, by any suitable cooling medium, such as airor gas, to the end that unusually large amounts of energy may withsafety and forlong periods be passed through the tube withoutendangering vits life or structure and to the further end of procuringbetter behavior of a vacuum or X-ray tube, either with normal orexcessive amounts of energy, by preventing the vacuum from varyingmaterially or widely from a lpredetermined or desirable degree.

To these ends I provide means for conducting the cooling medium to theelectrodes within the vacuum or X-ray' tube by structure of thecharacter hereinafter described. And it is a further feature of myinvention that I provide a stream or blast of cooling medium over theexterior walls of the vacuum or X-ray tube, and particularly over theregion of union between the bulb proper and the cathode stem, or overthe region approximatethe cathode where, under normal conditions, localheating of the glass occurs which is likely to cause devitriication ofthe glass with resultant lowering of the vacuum or rendering the vacuumerratic and1 changeable, or cracking of the glass wal For anillustration of one of the forms my invention may take reference is tobe had to the accompanying drawing, in

which:

Figure 1 is a longitudinal sectional View taken through an X-ray tubeembodying my invention. Fig. 2 is a cross sectional view taken on theline 'X-X of Fig. 1. Fig. 3 is a cross sectional View on the line Y-Y ofFig. 1.

Referring to the drawing, B is the usual glass bulb of an X-ray tubehaving the usual glass anode stem D and the usual glass -cathode stem Eand a vacuum regulator R.

Within the tube are the usual anode or target A and cathode C.

In the example illustrated the head 1, of copper -or other suitablematerial is secured toa metallic tube 2, as of steel, whichfits over thetubular glassstem 3 joined to the stem D at 4.- A tube 5, of copper orother suitable material, is set into the head 1 and preferably Weldedthereto forming a vacuum tight joint. The tube 5 extends through thestem D and at its end is Welded or soldered at a vacuum tight joint tothe platinum or other tube 6 which is sealed into the end of the glassstem D forming a vacuum tight joint. A corrugation 6 in the tube 6yields, under expansion and contraction' of the tube 5 due totemperature changes, and thereby prevents breakage of sea-l between tube5 and glass stem D. Within thel tube 5 is disposed a metallic tube 7which at its inner end has any suitable metallic projection 8 formingelectrical contact with the tube 5 or head 1. Near its outer end thetube 7 is connected, as by soldering or brazing, to the metallic ferrule9 embracing the end of the glass stem D. Electrical connection is madefrom the positive terminal of a suitable high tension source of currentwith the ferrule 9 or the tube 7. The extreme end of the tube 7 isconnected by rubber hose or -otherwise with a supply vof any suitablecooling medium,

for example, a supply of air under pressure.

Accordingly the air will pass into and through the tube 7, strike thehead 1, from which the tube 7 is suitably spaced, eX- tracting heat fromthe head1 which conducts the heat away from the target proper, the airthen passing outwardlyas indicated by the arrow through the annularspace between the tubes 5 and 7 to theouter air through perforationsI 10in the cap or ferrule 9.-

`The cathode C is counterbored to receive the tube 11 of copper or othersuitable ma? terial, there being a vacuum tight joint between thecathode C and the tube 11 as by welding, brazing, soldering, etc. At itsother end the tubeell is welded, soldered or brazed to the platinum tube12 sealed in the outer end of the glass cathode stem E making vacuumtight joints. Within the tube 11 is a metallic tube 13, spaced at itsinner end from the cathode -C and having the projection 14 makingelectrical connection with the cathode C or the tube 11.

4other suitable material.`

the aforementioned source of currentwith the ferrule 14 or the tube 13which communicates electrically with the cathode C. The sleeve or tube15 is supported llpOn the glass cathode stem E by the member 16, 0f Corkor other suitable material, which has a plurality of longitudinallyextending grooves 17 forming air passages. The tube or sleeve 15preferably terminates in the bell 18 which extends around "the bulb B toany suitable distance.

Air or other cooling medium is introduced into the tube 13, passestherethrough and strikes the cathode C, cooling the same, and thenpasses outwardly in the annular space between tubes 11 and 13 into thesleeve or tube 15 thence through the passages 17 over the outside ofthe' cathode stem E into the bell 18 from which it issues over the outersurface of the bulb B, all as indicated by the arrows. And I have foundthat the air or other medium issuing from the bell 18 clings or remainsclose to the bulb B even beyond its middle or equator.

By this construction not only is the cathode C cooled, but the glass ofthe stem E or bulb B near theirjunctiornas at 19,` that is, in theregion near the outer margins or rim of the cathode C is kept cool, sothat it cannot rise to that temperature at which decomposition ordevitriication of the glass takes place, and consequently the vacuumwithin the tube is prevented from lowering or varying, with the resultthat the X-ray tube Aoperates with substantial uniformity under eithernormal .or above normal excitation or for long periods.`

I have found that with an X-ray tube constructed as above described thatwhen a current of 1() fmilliamperes was passed through the., tubecontinuously for four hours,l the vacuum at the end of the run was ashigh as at the start. I found that the tendency was for the vacuum tobecome higher, that is, rarer, and it was necessary to regulate thevacuum of the tube fre quently, as by vacuum lowering regulator R, tokeep the vacuum down to the same degree as atthe start of the run.

T'o those skilled in the operation of X-ray tubes this will beunderstood to be a desirable advantage for, las is well understood,

when an X-ray tube is energized continuously for some considerable timethe tube becomes hotwhich causes the cvacuum to lower.

' by my invention this tendency to um when the tube has been run forsuch rlengthof time as would cause it,'without my improvement, to beheated to such degree as to cause erratic or undesirable behavior.-

What I claim is:

1. The combination with a vacuum tube having an electrode, of a hollowsupport for said electrode and a conduit. for cooling mediumcommunicating with the interior of said hollow support and surrounding apart of the vacuum tube at its exterior.

2. The combination with a vacuum tube having an electrode, of a hollowsupport for said electrode, a conduit for cooling medium communicatingwith the interior of said hollow support and surrounding a part of thevacuum tube at its exterior, and a second conduit for cooling mediumextending into said hollow support.

3. The combination with a vacuum tube having an electrode, of a tubularmember supporting said electrode, and an outer sleeve embracing andspaced from theexterior of the vacuum tube and communicating with theinterior of said tubular member.

4. The combination with a vacuum tube having an electrode, of a tubularmember supporting said electrode, an outer sleeve embracing and spacedfrom theexterior of the vacuum tube and communicating with the interiorof said tubular member, and a tube for cooling medium extending intosaid tubular member.

5. The combination with' a vacuum tube having an electrode, of a stem onsaid tube, a hollow support for said electrode, a sleeve surrounding andspaced from said stem and communicating with the interior of said hollowsupport.

6. The combination with a vacuum tube having an electrode, of a stem onsaid tube,

ahollow support for said electrode, a sleeve low support, and a bell onone end of said sleeve.

8. The combination with a vacuum tube having an electrode, of a stem onsaid tube, a hollow support for said electrode, a sleeve surrounding andspaced from said stem and communicating with the interior of said hollowsupport,`a tube for cooling medium extending into said hollow' support,and a bell on one end of said sleeve.

9. The combination with a vacuum tube having an electrode, of a stem onsaid tube,

a hollow support for said electrode, a sleeve surrounding and spacedfrom said stern and communlcatingA with vthe interior of sald hollowsupport, and a perforated support for said sleeve upon said stem.

10. The combinationwith a vacuum tube having an electrode, of a stem onsaid tube,

the junction of said stern and bulb, a tubular support for said cathode,a sleeve spaced from and embracing said stem, the interior of saidtubular support communicating with the` space between said sleeve andstem.

12. The combination with an X-ray tube comprising a bulb and stem, of acathode Within said tube and disposed approximate the junction of saidstem and bulb, a tubular support for said cathode, a sleeve spaced fromand embracing said stem, the interior of said tubular supportcommunicating With the space between said sleeve and stem, and a tubefor cooling medium extending into said tubular support.

13. The combination With an X-ray tube comprising a bulb and stem, of acathode Within said tube and disposed approximate the junction of saidstem and bulb, a tubular support for said cathode, a sleeve spaced fromand embracing said stem, the interior of said tubular supportcommunicating with the space between said sleeve' and stem, and a bellon said sleeve approximate the junction of said bulb and stem.

let. The combination with an X-ray tube comprising a 'bulb and stem, ofa cathode within said tube and disposed approximate the junction of saidstem-and bulb, a tubular support for said cathode, a sleeve spaced fromand embracing said stem, the interior of said tubular supportcommunicating with the space between said sleeve and stem, a tube forcooling medium extending into said tubular support, and a bell on saidsleeve approximate the junction'of said bulb and stem.

'stem and communicating with the interior of said support, and a tubefor cooling medium extending through said' closed end of said sleeveinto said support.

16. The combination With an X-ray tube comprising a bulb and stem,fof anelectrode l Within said tube, a tubular support for said electrode, asleeve spaced from and` embracing said stem, said sleeve being closed atits end approximate the outer end of said stem and communicating withthe interior of said support, a tube for cooling medium extending'through said closed end of said sleeve into said support, and a bell onsaid sleeve approximate thejunction of said bulb and stem.

17. The combination with an X-ray tube,

.of a tubular support integral with the walls thereof, an anti-cathodehaving a tubular extension, said tubular support extending into saidtubular extenslon, a second tube on said anti-cathode sealed in the Wallof said X-ray tube and opening to the atmosphere, the gas pressure ofsaid X-ray tube existing within said tubularl support and extension, athird tube'within said second tube,

said second and third tubes being so disposed and spaced that coolingmedium may be passed therethrough.

18. The combination with the bulb of an X-ray tube, of a stem integralwith said bulb, a tube sealed at its one end in said stem, the free endof said .tube disposed within said bulb, a yielding connection betweensaid tube and said stem near the seal of said tube in said stem, anelectrode attached to the free end of said tube within said bulb andformingva closure for saidtube, a tubular support integral with saidbulb, and a tubular extension onsaid electrode carried by said tubularsupport.

19. The combination with the wall of an X-ray tube, of a tube sealedtherein, an

anti-cathode attached to the end of said tube and forming a closureforssaid tube, a stem integral with the X-ray tube extending into saidX-ray tube, and a tubular extension on said anti-cathode engaging saidstem.

20. The combination with an X-ray tube,

of a tubular support integral with the wall thereof, an electrode havinga tubular extension carried by said tubular support, the gas Apressureof the X-ray tube existing Within and without said tubular support andextension, and a hollow member opening to the atmosphere attached tosaid electrode within said extension and sealed into a Wall of saidX-ray. tube. i v

21. The combination with an X-ray tube, of a tubular support integralWith the Wall thereof, an electrode having a tubular extension carriedby said tubular support, the gas pressure of the X-ray tube existingwithin and Without said tubular support and extension, and a tube havinga vacuum tight joint with said electrode and sealed in a Wall of saidX-raytube.

22. The combination with a vacuum tube comprising a bulb, of a sleevesurroundin and spaced from said vacuum tube, sai

sleeve terminating in a bell for directing cooling medium over said bulbbeyond the end of said bell.

23. The combination with a vacuum tube comprising a bulb, of a bellspaced from and bomprising a bulb and a stem, a sleeve surrounding andspaced. from said stem, said sleeve terminating in a bell partly'surrounding said bulb, and means delivering cooling medium through saidsleeve to said bell, said bell directing said medium over said bulbbeyond the end of said bell.

25. The combination With a vacuum tube, of a stem on said tube, a sleevesurrounding and spaced from said stem, said sleeve olosed at-its one endand open at the other, said sleeve at its closed end inclosing the 'freeend of said stem, and means vdelivering cooling medium into said sleeveat its closed end.

26. The combination with a vacuum tube, of a stem on said tube, a sleevesurrounding and spaced from said stem, said sleeve closed at its one endand open at the other, Said sleeve at its closed end inclosing the freeend of said stem, means delivering cooling medium intosaid sleeve at itsclosed end, and a perforated support for said sleeve upon said stem.

In testimony whereof I have hereunto affixed my signature in thepresence of the two subscribing Witnesses.

, ELEANOR T. MCCALL,

NELLIE FIELD.

